SHELL

while loop bash

while true;
do
	#code
done

while loop shell script

#!/bin/sh

a=0

while [ $a -lt 10 ]
do
   echo $a
   a=`expr $a + 1`
done

bash while loop

#!/bin/bash
i=0
While [ $i -le 10 ]
do
 echo i:$i
 ((i+=1))
done

bash while done

while CONDITION_STATEMENT; do SOME_CODE; done

While loops in bash

#!/bin/bash
X=0
while [ $X -le 20 ]
do
	echo $X
	X=$((X+1))
done

for while bash

Use for in bash for iterating words in a string or values in an array as:
for value in {1, 2, 3}; do echo $value; done
for value in $(cat arguments_files.txt); do [some_command]; done
And use while for iterating lines from a pipe output as:
cat arguments_file.txt | while read line; do [some_command]; done

bash while

#!/bin/bash
counter=$1
factorial=1
while [ $counter -gt 0 ]
do
   factorial=$(( $factorial * $counter ))
   counter=$(( $counter - 1 ))
done
echo "$factorial"

linux while loop shell

while ! [ "${finished}" ]; do
    ...
done

linux while loop shell

finished=false
while ! $finished; do
    ...
    # At some point
    finished=true
done

linux while loop shell

while [ "$finished" != "true" ]; do
   ...
done